Nutrient Cycling in Agroecosystems

http://link.springer.com/journal/10705

List of Papers (Total 76)

Nitrogen fertiliser replacement values for organic amendments appear to increase with N application rates

Nitrogen (N) supply from organic amendments [such as farmyard manure (FYM), slurries or crop residues] to crops is commonly expressed in the amendment’s Nitrogen Fertiliser Replacement Value (NFRV). Values for NFRV can be determined by comparison of crop yield or N uptake in amended plots against mineral fertiliser-only plots. NFRV is then defined as the amount of mineral ...

Soil nutrient maps of Sub-Saharan Africa: assessment of soil nutrient content at 250 m spatial resolution using machine learning

Spatial predictions of soil macro and micro-nutrient content across Sub-Saharan Africa at 250 m spatial resolution and for 0–30 cm depth interval are presented. Predictions were produced for 15 target nutrients: organic carbon (C) and total (organic) nitrogen (N), total phosphorus (P), and extractable—phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), sodium ...

Nitrogen flows on organic and conventional dairy farms: a comparison of three indicators

This paper analyzes nitrogen (N) flows on organic and conventional dairy farms in Sweden, and compares three indicators for the N pollution associated with the milk: (1) the farm-gate N surplus, (2) the chain N surplus, and (3) the N footprint. We find that, compared to indicators based on N surplus, the N footprint is a more understandable indicator for the N pollution associated ...

Fallow replacement and alternative nitrogen management for reducing nitrate leaching in a semiarid region

Nitrate (NO3 −) leaching into groundwater is a growing global concern for health, environmental, and economic reasons, yet little is known about the effects of agricultural management practices on the magnitude of leaching, especially in dryland semiarid regions. Groundwater nitrate–nitrogen (nitrate–N) concentrations above the drinking water standard of 10 mg L−1 are common in the ...

Leaching losses from Kenyan maize cropland receiving different rates of nitrogen fertilizer

Meeting food security requirements in sub-Saharan Africa (SSA) will require increasing fertilizer use to improve crop yields, however excess fertilization can cause environmental and public health problems in surface and groundwater. Determining the threshold of reasonable fertilizer application in SSA requires an understanding of flow dynamics and nutrient transport in ...

N2O emissions from grain cropping systems: a meta-analysis of the impacts of fertilizer-based and ecologically-based nutrient management strategies

Understanding how agricultural management practices impact nitrous oxide (N2O) emissions is prerequisite for developing mitigation protocols. We conducted a meta-analysis on 597 pairwise comparisons (129 papers) to assess how management affects N2O emissions. Pairwise comparisons of practices aimed at improving fertilizer use efficiency (39%) and tillage (30%) dominated the ...

Soil nutrient balances under diverse agro-ecological settings in Ethiopia

Soil fertility is one of the main constraints to agricultural intensification in Ethiopia. Like in many East African countries, nutrient depletion rates are exacerbated in Ethiopia by high erosion rates, biomass and animal manure removal from farm plots and limited application of mineral and organic fertilizers. In this paper, soil nutrient balances at plot level were calculated ...

Emissions of nitrous oxide and ammonia after cauliflower harvest are influenced by soil type and crop residue management

The decomposition of vegetable crop residues, e.g. from Brassica species, can cause substantial nitrous oxide (N2O) and ammonia (NH3) emissions due to their high nutrient and water contents. One promising approach to reduce these harmful emissions is optimizing post-harvest crop residue management. So far published results on the effects of different crop residue placement ...

Does balanced phosphorus fertilisation sustain high herbage yields and phosphorus contents in alternately grazed and mown pastures?

Many soils of agricultural land in affluent countries have been enriched with phosphorus (P), because P application via fertilisers and manures was larger than P withdrawal via harvested biomass. This practice threatens the long-term availability of P fertilisers derived from finite rock phosphates, as well as surface water quality because of P leaching and run-off losses. In ...

Long term effects of reduced fertilizer rates on millet yields and soil properties in the West-African Sahel

Microdosing, the point-source application of a reduced fertilizer rate within 10 days of sowing, has increased short-term crop yields across the Sahel and is being actively scaled up as an agronomic practice. However, there is no information on the long-term effects of the technique upon soil fertility. To rectify this, this study used soil samples from the International Crop ...

Long-term effects of TSP and Minjingu phosphate rock applications on yield response of maize and soybean in a humid tropical maize–legume cropping system

Crop production in sub-Sahara Africa is constrained by low soil phosphorus (P) content. A study was conducted in western Kenya to explore alternative P inputs and ways of optimizing their effectiveness and profitability. A field experiment established in 2007 studied the effects of Minjingu phosphate rock (MPR) and triple superphosphate (TSP) on maize, common beans and soybean ...

Landscape-scale variability of soil health indicators: effects of cultivation on soil organic carbon in the Usambara Mountains of Tanzania

Land-use change continues at an alarming rate in sub-Saharan Africa adversely affecting ecosystem services provided by soil. These impacts are greatly understudied, especially in biodiversity rich mountains in East Africa. The objectives of this study were to: conduct a biophysical baseline of soil and land health; assess the effects of cultivation on soil organic carbon (SOC); and ...

Combining micro-bottom-up and macro-top-down modelling responses to nutrient cycles in complex agricultural systems

Concerns over the long-term sustainability of the food production system and the nutritional content of food from mineral depleted soils have encouraged a policy shift to sustainable agricultural practices where soil health supports nutrition-sensitive agriculture. Interventions at the micro scale have the ability to affect the entire system, forcing an examination at the whole of ...

A multi-regional soil phosphorus balance for exploring secondary fertilizer potential: the case of Norway

Phosphate rock is a non-renewable source of phosphorus (P) in mineral fertilizer and many countries need to use P fertilizer more efficiently in food production. This study explored the theoretical fertilizer potential of the P-rich bioresources animal manure and sewage sludge to supply the required P fertilizer for crops. We used Norway as a case study and employed multi-regional ...

A substance flow analysis of phosphorus in the food production, processing and consumption system of the Netherlands

Phosphorus (P) is an essential nutrient in agriculture. In recent years 15–18 Mt of P was used as mineral fertilizer in the global food production chain. The major source of this fertilizer is phosphate rock which is unfortunately a finite resource. In the long term this necessitates efficient use of fertilizer and optimized recycling of P rich waste streams (including manure). In ...

Combining mechanical control of couch grass (Elymus repens L.) with reduced tillage in early autumn and cover crops to decrease nitrogen and phosphorus leaching

Methods for control of couch grass (Elymus repens L.) with reduced tillage and cover crops to achieve low risk of nitrogen (N) and phosphorus (P) leaching were investigated. Treatments with reduced post-harvest tillage (one or two passes with duckfoot cultivator), hoeing between rows in combination with a cover crop, and a cover crop mown twice during autumn were compared with ...

Bringing ISFM to scale through an integrated farm planning approach: a case study from Burundi

Integrated soil fertility management (ISFM) is generally accepted as the most relevant paradigm for soil fertility improvement in the tropics. Successes however are mainly reported at plot level, while real impact at farm level and beyond remains scattered. As a consequence, many Sub-Saharan African countries continue experiencing soil nutrient mining and insecure and insufficient ...

Climate-smart crop production in semi-arid areas through increased knowledge of varieties, environment and management factors

In large regions of sub-Saharan Africa, semi-arid conditions are likely to increase with climate change, yet these regions are becoming more important to feed production zones due to increasing population pressure. A production system in the semi-arid south eastern Zimbabwe was studied to assess different possible growth conditions of food crop in relation to seasonal differences, ...

Legume, cropping intensity, and N-fertilization effects on soil attributes and processes from an eight-year-old semiarid wheat system

In the North American northern Great Plains (NGP), legumes are promising summer fallow replacement/cropping intensification options that may decrease dependence on nitrogen (N) fertilizer in small grain systems and mitigate effects of soil organic matter (SOM) losses from summer fallow. Benefits may not be realized immediately in semiarid conditions though, and longer-term effects ...